Radio-receiving apparatus



Jan, 1925.

H. F. LOWENSTEIN ET AL RADIQRECEIVING APPARATUS Filed Aug. 14, 1922 Patented Jan. 6, 1925.

UNITED STATES PATENT OFFICE.

) HARRY F. LOWENSTEIN AND EDWARD E. CLEMENT, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNORS, BY DIRECT AND' MESNE ASSIGNMENTS, TO EDWARD F.

COLLADAY, OF WASHINGTON, DISTRICT OF COLUMBIA.

RADIO-RECEIVING APPARATUS.

Application filed August 14, 1922, Serial No. 581,773. Renewed July 22, 1924.

To all whom it may concern.

Be it known that we, HARRY F. LOWEN- srnnv and EDWARD E. (/LEMENT, citizens of the United States, residing at Washington, in the District of Columbia, have invented certain newi and useful Improvements in Radio-Receiving Apparatus, of which the following is a specification, reference being had therein to the accompanying drawing.

Our invention relates to combined radiophone and telephone systems, and has for its object the provision of improved means by which an operator at a radio switchboard may supervise the operation of a radio receiving apparatus at a subscribers station.

It has been proposed in such systems to provide a test or llstening relay at the subscribers station, connected to the telephone wire circuit and controlled by a radio operator at central to connect the substation radio receiving apparatus or circuits to the wire circuit for telephonic transmission thereover to central, whereby the said radio operator may listen to the actual sounds received and reproduced at the substation while broadcasting, with a view to the regulation and adjustment of the transmitting instrument or the receiving instrument, or both. In the present case, we provide for such supervision by connecting a telephone transmitter to the contacts of the listening relay, and so relating said transmitter to the receiver or loud speaker of the radio receiving set that air conduction of sound waves takes place between them, and a test of the complete performance of the apparatus as a whole is possible.

Our invention is illustrated in the accompanying drawing, in which the figure is a diagram showing a central office having a telephone switchboard and a radio switchboard, a subscribers station equipped with a telephone and a radio receiving set, and the line circuit therefrom to central.

Referring to the drawing, C is the central oflice which for convenience is shown equipped with manual apparatus, but which may have automatic switching apparatus, for the interconnection of telephone lines, or for the radio station control, or both. The line 16-17 is connected as usual to terminals on the telephone switchboard and to one or more multiple terminals on the radio switchboard, where the radio operator has cord circuits typified at Pm, equipped with a switch Km for connecting battery to the tip slde' of line, the cut off relay of the line being at the same time energized to clear said side of ground at the central office, which is normally connected through the windings of the line relay.

At the substation A, the telephone T is a standard common battery instrument set. The radio receiving apparatus is equipped with another telephone set, comprising a transmitter T, receiver 15', induction coil I, hook switch H and condensers g 9 The radio set in itself forms no part of the present invention, but to supply a loud speaking horn for our purposes, is shown as having a detector tube 30, and two stages of audio amplification by tubes 31 and 32. The usual transformers 33, 34, 35 are provided, with batteries A and B for filaments and plates. The horn 36 and the switch hook H are so related that when the telephone T is hung on the hook it will be in position to receive sound waves from the horn. When the hook H is [Up it closes the filament circuits as follows: A 25, 42, H, 41, filaments, battery. Vhen the hook is down, the radio operator at central can close the filament circuit and also the circuit of transmitter T by pulling up relay L For this purpose, key Kan-is closed, and battery current flows over tip side 16 of line to the substation, thence through back contact of cut off relay L by wire 26 to L and ground. L becoming energized, closes the following circuits: filament circuit from A, 25, 27 37, 43; transmitter circuit froirrA to 25, 27", T, I, and back to battery, shown as by ground return, but may be by wire; line transmission circuit: 16 contact of L, 26, 27, 39, g, t, I, 9 40, 2 back contact of L*, and so to sleeve side 17 of line. The operator thus controls both the filament circuit and the repeat back circuit, and as the telephonic connection between the line and the radio set includes the horn 36, a complete test is available of the entire apparatus and the actuali tones produced thereby.

-REI'SSUED lVe claim:

In a combined radio and telephone system, a central station, a subscribers station, a wire circuit connecting them, a radio receiving set at the subscribers station, and a telephone transmitter related thereto so as to receive sound waves therefrom, with means controllable by a radio operator at the central station to close the circuits of said transmitter for current supply thereto and 10 for telephonic transmission over the wire circuit to central.

In testimony whereof our signatures.

HARRY F. LOWENSTEIN.

EDWARD E. CLEMENT.

we hereunto affix 

